Improved galvano-plastic pkooess foe peecipitating leon on moulds



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RUSSIA, ASSIGNORS T0 GREEN, CLAY, AND COMPANY.

Letters Patent No. 82,525, dated September 29, 1868.

IMPROVED GALVANO-PLASTIG ?ROGESS FOB. PREUIPITATING IRDN 0N MOULDS, 8:0.

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TO ALL WHOM IT MAY CONCERN:

Be it known that we, MAURICE Ha'nnMANN Jsoom and EUGENE KLEIN, of St. Petersburg, in Russia, have invented a new and u'seful Improvement in Galvano-Plastic.Process for Preeipitating Iron on Moulds, &c.; said we do hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in the art to make and use the same, reference being had to the accompanying drawings, forming part of this specification.

Our invention consists in the application of a practical galvano-plastic process as to the deposits of iron" on moulds, or any other form, for reproducing engravings, stereotypes, and for other useful or ornameral purposes.

'lhc galrano-plastic bath we use is composed of sulphate of iron, combined with the sulphates of either ammonia, iotash or soda which form with sul hate of iron aualo ou's double salts.

l 7 1 P i c The sul ihatc of iron ma also be used in combination with the chlorides of the said alkalies, but we still a l y v prefer the use of sulphates.

The bath should be kept as neutral as possible, though a small quantity of a-weak organic acid may be.

added, in order to prevent the precipitation of salts of peroxide of iron.

A small quantity of gclatinc will improve the texture of the iron deposit.

As in all galvano-plastic processes, the elevation of the temperature of the bath contributes to the uniformity of the deposit of iror i, and accelerates its formation.

For keeping up the concentration of the bath, we use, as anodes, large iron plates, or bundles of wire of the same metal. I

Having observed that the spontaneous dissolution of the iron anode is, in some cases, insufficient to restore to the bath all the iron deposited on the cathode, we found it useful to combine the iron anode with a plate of gas-coal, copper, platinum, or any other metal being electro-negativctowards iron, and which we place in'the bat h itself. I

As a matter of course, this negative plate may also bcvplaccd in a. separate porous cell, filled'with an exciting fluid, as diluted nitric or sulphuric acid, or the nitrates or sulphates of potash and soda.

For producing the current, we usually take no more than one or two cells of Daniels 0'! Smees battery, the size of which is proportioned to the surface of the cathode.

it is indispensable that the current should be regulated, and kept always unii'orm, with the assistanceof a I galranomctcr, having but few coils, and therefore offering only asmallresistarice.

The intensity of the current ought to be such as to admit only of a feeble evolution of gas-blihbles zit-the cathode, but it would become prejudicial to the beauty of the deposit if gas-bubbles were allowed to adhere to its surface. ,v

The same moulds, as employedfor depositing copper, may also he used for-dcpositiug iron, onlyit is admisable, in employing moulds made of lead or gutta percha, to cover them previou ly with quite a thin film of galvaniccoppcr, formed, ina few minutes, in the usual way, and then bring them, after having washed the moulds with water, immediately in the ironbath. i v I This film of copp-ormay be removed from the deposit either by mechanical means, or by immersion into strong nitric acid. 7 l

'lhc deposited iron is very hard, and rather brittle, so that some precaution must be taken in separating it from the mould. Byncaling, it acquires the mallcability and softness of tempered steel.

Having thus described our invention, we claim as new, and desire to secure by Letters Patent- The process of precipitating iron on moulds, in the manner substantially as and for the purposes heroin set forth.

MAURICE HERRMANN JAGOBI.

EUGENE KLEIN.

Witnesses:

Josneu Lxsnssr, Viewer. llAitMANN. 

